This invention relates to an apparatus for retracting and extending a flexible member, and more particularly to a system for at all times maintaining the proper amount of conduit connection between a fluid power system mounted on a first vehicle and a fluid power receiving device mounted on a second vehicle.
This invention is particularly useful in providing electrical, pneumatic or hydraulic connections, such as those required for braking systems, between a truck tractor and one or more detachable truck trailers. In a typical situation, the tractor has a pneumatic power braking system, including one or more fluid pressure outlets, to which hoses are connected for transmitting the effects of the fluid pressure to a fluid pressure receiving device, such as the pneumatic brakes, on a trailer pulled by the tractor. Because of the pivotal connection between the tractor and trailer, a certain amount of excess hose must be provided to take into account variations in the distance between the hose connections. This excess hose is usually allowed to either hang loosely between the tractor and trailer or is formed into a coil which has a resiliency of its own. In this manner, an excess of hose is available when the tractor and trailer assume different positions with respect to each other during turning or when occupying different levels on the terrain.
Such current methods, however, fail to provide the protection necessary to such hoses, both during use and storage, with the result that the hoses wear through by abrading against adjacent parts of the truck or trailer, are cut when caught between moving parts of the tractor and trailer, or otherwise become damaged. This necessitates changing the hoses annually as a safety precaution against more disastrous effects where hoses break unexpectedly which effects include brake locking due to the failsafe configuration employed in current tractor-trailer systems. According to a recent survey, twenty one percent of all truck accidents were caused by brake failure resulting in an average damage to the tractor-trailer unit of over $2,000.00. Thirty five percent of these brake failures were known to be due to some type of failure in the hydraulic or pneumatic connecting systems between the tractor and trailer. Such loss figures do not include other damages, such as personal injury, property loss, and loss of time.